The present invention relates to a testing method and a testing device wherein a detection of foreign substances in a solution filled in a vessel such as an ampoule, vial and the like and a detection of the leakage or the pinhole of the vessel itself are performed with higher accuracy.
Generally, when a solution filled in a vessel which is transparent or semi-transparent is examimed, the vessel is irradiated with light, an output signal is obtained corresponding to the quantity of the light passed through the vessel, and the output signal is compared with a prescribed standard value for judging.
In the above method, the quantity of light and the wavelength of light from a projector as the light source vary as the time goes. A projector newly set and a projector whose irradiation energy is decreased after a certain period has elapsed give different output signals. Therefore, if the standard value is always set constant as ever, the judgement of the subject is not so accurate that even a good subject may be misjudged to be inferior.
For an examination of a pinhole or leak of a vessel itself such as an ampoule or vial for a solution of chemical or food, said vessel is dipped into a dense dye solution for example of methylene blue or blue dye for food, and made vacuum once, and then brought back into the normal pressure. The dense dye is introduced into the interior of the vessel through small holes, cracks and gaps which can be inspected or observed with the spectrophotometry.
In the inspection method, the degree of experience and the physical condition of an inspector influence the results of examination. Also this method is extremely inefficient.
In the spectrophotometry, the output signal is affected by changes of the projector lamp and the circuit composing element such as photodiodes, photoelectric bulb and the like of the measuring circuit system with the lapse of time and by the environmental temperature change.
Therefore, the result of measurement is changed by the characteristics of these circuit system composing elements.
Further, since the coloured solution has its absorption easily affected by the environmental temperature variation, the results of measurement is influenced by the temperature at the time of measurement leading to a phenomenon in which a good subject is misjudged to be inferior.